Automatic milking takes place in a milking parlor which is provided with a milking robot typically comprising a robot arm functioning as a carrier of one or several teat cups to be applied to the teats of an animal's udder. The teats are located by means of one or several sensors, whereupon the robot arm--swung from a side of the milking parlor to underneath the animal--can be positioned so that through an upward movement of an appropriate teat cup said teat cup can be applied to a teat of the animal's udder. In order to control the process of connecting the teat cups, the milking process itself, and the physical constitution of the cows, according to the invention, the implement is characterized in that in the line system from a teat cup down to the location where the milk lines from the teat cups join there is provided one or more sensors including a vacuum-sensitive sensor, a flow-sensitive sensor, a temperature-sensitive sensor, an electrical conductivity sensor. A computer is also provided for processing and reproducing the information produced by these sensors. Such a line system may be provided for each of the quarters of the animal's udder. The sensors may be placed in only one line and consequently relate to the flow of milk from only one teat, but they may also be placed in several lines from individual teat cups and then relate to the flow of milk from several teats. When the flows of milk from the individual teats are combined in a milk claw, the sensors should be placed in one or several teat cups and in the relatively short lines from said teat cups to the milk claw; if desirable, the milk claw may comprise separate compartments to accommodate sensors for each of the quarters of the animal's udder, with the milk from these compartments joining together in a further part of this milk claw. When the milk from the individual teats is fed through separate lines to a common milk meter, the sensors in one or several teat cups and in these separate milk lines should be placed before the connection to the milk meter. When separate milk meters are used for the milk flows from the various teats the flow of milk leaving such a milk meter is fed into a central milk line and the line system in which sensors may be included is considerably longer. It should be kept in mind, however, that the location of the sensors is also determined to a large extent by the nature of the sensor. The temperature-sensitive sensor, for example, should not be placed too far downstream from a teat cup, because the milk will have cooled down too much there and the information from this sensor will thus be of little value.
According to another aspect of the invention, the implement can be provided with a vacuum-sensitive sensor for each of a plurality of teat cups, to detect the presence and/or a vacuum drawn amount therein. For a set of teat cups, the implement may be provided with a vacuum-sensitive and a flow-sensitive sensor combined with a computer to determine the dead time associated with the flow of milk. However, for each of a plurality of teat cups, the implement may also comprise a combination of a vacuum-sensitive and a flow-sensitive sensor to determine, in association with a computer, the dead time with regard to the flows of milk in the relevant teat cups.
According to a further aspect of the invention, the implement can include a temperature-sensitive sensor for one or several teat cups to determine the temperature of the relevant flow of milk, and also a computer to determine the dead time and, in conjunction with the information originating from the temperature-sensitive sensor, to produce an indication of an abnormally high temperature indicating a physiological condition in the animal. Furthermore, there may be provided for one teat cup or for each of a plurality of teat cups a combination of a temperature-sensitive sensor and a sensor to determine the electrical conductivity of a flow of milk, by means of which combination, in association with a computer, mastitis may be detected in one or several quarters of the animal's udder.
A further problem encountered when attempting to apply a teat cup is that sometimes the attempt to apply the teat cup correctly to an appropriate teat is unsuccessful.
This invention provides the capability to detect and resolve this problem as described hereinafter. As soon as a teat cup has been applied to an appropriate teat of the animal's udder, a vacuum is drawn in the teat cup, the presence of which vacuum is detected by a vacuum-sensitive sensor. However if, the vacuum-sensitive sensor does not detect the presence of a vacuum, which indicates that the teat cup has not been applied or has not been applied appropriately, one or more subsequent attempts may be made to apply the teat cup to the relevant teat, possibly preceded by a renewed determination of the teat's position in respect of the teat cup which is carried by the robot arm and is to be applied to this teat. Indication of the presence or absence of a sufficient vacuum may be provided by supplying a signal produced by the vacuum-sensitive sensor to a computer which controls the robot arm.
However, even if a sufficient vacuum has been detected by the vacuum-sensitive sensor, it may happen that the teat cup is not correct ly connected. For there is a possibility exists that the teat cup is connected to a folded-up teat pressed against the udder, so that the teat is not appropriately seated in the teat cup, whereas a sufficient vacuum may still be drawn in the teat cup. This situation, may also be detected according to this invention as follows:
After a teat cup has been applied to the appropriate teat, the start of the milk flow is detected by means of a flow-sensitive sensor, whereas, in the event that, within a predetermined time from the connection of the relevant teat, the milk flow from this teat has not started, the teat cup is disconnected and applied anew. In disconnecting and re-applying the teat cup, the teats should be distinguished from each other. When the teat cups are installed from one side with respect to the animal's udder the teat cups may be led underneath the teats concerned and be applied to them, but, when one of the teat cups to be disconnected is to be re-applied to a hindmost teat this teat cup may be impeded by the foremost teat cup that is already connected. If this situation occurs first the two foremost teat cups are disconnected, then the hindmost teat cup is connected and finally, the two foremost teat cups are re-applied. In other words, if a hindmost teat cup needs to be disconnected to be re-applied, this can be done after first disconnecting the foremost teat cups, primarly because of a lack of space; whereas if a foremost teat cup needs to be disconnected and re-applied, this can be done immediately. However, when the distance between the foremost teats is sufficiently large, such that re-applying a hindmost teat cup is not impeded, it will not be necessary to take the foremost teat cups away first. When the position of a teat has been determined, a teat cup is connected to this teat through means provided for this purpose, these means being part of the milking robot.
According to the invention these means, e.g. an electromagnet gripping the teat cups individually and being moved upwards hydraulically as described in EP-A-0 360 354, remain activated until the presence of a sufficient vacuum in the teat cup has been established by the vacuum-sensitive sensor, whereas in the event that not a sufficient vacuum has been established after a certain time lapse of e.g. a few seconds, it will again be attempted to connect the relevant teat cup by a renewed activation of said means. After a correct connection of a teat cup to an appropriate teat has been made, the vacuum can be continuously tested in order to obtain an indication signal when the teat cup falls off before the flow of milk has stopped, e.g. owing to the fact that it is kicked away by the animal.
The time lapse from the instant when a teat cup is connected to a teat to the instant when the flow of milk from this teat starts is called the dead time. This dead time can be determined by means of a computer. Accordingly, the invention also relates to a method of milking animals, especially cows, automatically, where the dead time between the instant when one of the teat cups is connected to an appropriate teat and the instant when the flow of milk from this teat starts is determined by means of a computer. In particular, the dead time between the instant when the vacuum-sensitive sensor has established a sufficient vacuum in a teat cup applied to a relevant teat and the instant when a flow-sensitive sensor has detected that the milk has begun to flow is determined by means of a computer. It will be sufficient to determine the dead time with respect to the start of the milk flow in the teat cup last applied. The idea behind this is that the dead time with respect to the last teat cup will be much the same as the dead time determined for the application of the other teat cups. It will be more correct, however, to determine. the dead time for the flow of milk from each of the teats.
In actual practice there appear to occur situations associated with the physical condition of the animals, which cause relatively large differences in dead times with regard to the start of the milk flows from the various teats. Of course, the situation where e.g. the last teat cup has not been applied correctly, or not at all, with the result that the animal cannot be milked at all, while the flows of milk in the teat cups connected first have already started, may occur at any time. Nevertheless, the animal should then leave the milking parlor. As far as the dead times which have been established relative to the flows of milk which did start, further conclusions may of course be drawn therefrom.
According to another aspect of the invention, the extent to which the dead time has exceeded a predetermined value for a particular animal can be determined by means of the computer. In particular, for each of the flows of milk from the various teats, the extent to which dead time exceeds the predetermined value is determined. This predetermined value will be different not only for various animals, but it will also change as the animals age. The farmer, however, will be basically interested only in those cases where the predetermined value is exceeded. When an animal is estrous or ill, the dead time will generally be longer than usual. If the predetermined value of the dead time has been exceeded by a certain percentage, the farmer has accordingly obtained an indication signal of the animal's heat or illness.
If a relatively long time, for example, twice the dead time determined previously for the animal, has elapsed after the vacuum in the teat cup has been established, then the computer draws the conclusion that the dead time cannot be determined, because the flow of milk has apparently not started, which may happen when an animal just milked has entered the milking parlor again. The animal should then be led away from the milking parlor.
According to the invention, a more reliable indication signal of heat or illness is obtainable from parameters including one or more of the following: the milk rate of flow, the temperature of a milk flow, the milk yield, and/or the number of times per given time period that an animal pays a visit to the milking parlor or the food quantity consumed in the milking parlor. These parameters for ill or estrous animals are different from those for healthy and non-estrous animals. One or more of the parameters may be combined with the dead time and analyzed by a computer. In doing so, to achieve a higher accuracy, especially the temperatures of each of the flows of milk from the various teats can be determined. For the determination of the temperature, use is made of temperature-sensitive sensors to be arranged in the flow of milk. When the farmer has obtained an indication that the animal is ill or threatens to fall ill, it is important to know whether mastiris or any other disease is involved. According to the invention, an indication that an animal suffers from mastiris can therefore be obtained in the computer by means of a sensor for electrical conductivity of the milk flow and, if necesary, also by means of a temperature-sensitive sensor. In particular, the electrical conductivity of the flow of milk from each of the teats can be determined. Furthermore, the computer can also determine to what extent the electrical conductivity of a flow of milk has exceeded a predetermined value for a particular animal. In order to exclude short-lived fluctuations as well as any highly gradual change in electrical conductivity of the flow of milk, this predetermined value is repeatedly re-defined by the progressive average of the relevant values established in the immediately preceding period of time, for instance, that of the latest ten measurements of electrical conductivity made. As a matter of fact, this also applies to the predetermined threshold values of the dead time.
Not only can the flow-sensitive sensor be used for establishing that a flow of milk has started, but also for establishing that a flow of milk has stopped. According to this invention, such a stop of the flow of milk is indicated to the computer, which ensures that the relevant teat cup is disconnected after the lapse of a certain period of time, (for example, two to sixty seconds), following the occurrence of this indication. The milk yield from the individual teats can thus be established. The function of the flow-sensitive sensor can be taken over by a milk meter; especially when the milk meter is capable of determining in small increments the quantity of milk produced. It then is possible to determine the milk yield, by calculating the difference between the starting and the stopping times of the flow of milk. It may also be desirable to have four milk meters to determine the milk yields from each of the individual teats.
The processing of the signals originating from the sensors by means of a computer permits that, at times randomly selectable by the farmer, the output can be displayed on the computer monitor or printed on a printer.
The data to be displayed or printed may include for example which animals and to what extent the dead time and/or the electrical conductivity of a flow of milk have exceeded their respective predetermined values. For example, the computer monitor or the printer could depict the following illustrative data a cow identified by number 25 gave evidence of an electrical conductivity which was 16% in excess of the predetermined value, a cow identified by number 100 gave evidence of an electrical conductivity which was 20% in excess of the predetermined value, a cow identified by number 150 gave evidence of an electrical conductivity which was 22% in excess of the predetermined value, etc. Similarly, it may be shown that a dead time for a cow identified by number 15 has been established which was 13% in excess of a previously determined value, that a dead time for a cow identified by number 38 has been established which was 8% in excess of a previously determined value, etc.
On the basis of the information on the electrical conductivity of a flow of milk, as given by the computer, the farmer can decide on whether or not the milk produced by a particular animal has to be drained off, for example into a waste tank. If the milk is determined to be unsatisfactory, it is fed through a computer-controlled three-way valve in a relevant milk line and drained off into e.g. a waste tank instead of being fed into a milk tank. When it is possible to establish that any quarter of an animal's udder suffers from mastiris, this permits the dairy farmer to discard only the milk from the quarter affected. This information may also be displayed on the computer monitor or on the printer. In addition to the aforementioned displayed or printed data on electrical conductivity and dead time, it can be indicated that for example, that milk from a cow identified by number 2 is being discarded, that milk from a cow identified by number 36 is being discarded, etc.
The invention will now be further explained with reference to the embodiment represented in the accompanying drawings.